The artist Spencer Tunick has probably photographed more naked people than any person on earth. You may have seen him fill Times Square with nude volunteers in an installation that HBO chronicled in a documentary. This past June Tunick’s work reached a new zenith when he photographed more than 7,000 nude people in Barcelona. Now, he’s back in the US working on a new, more intimate, series of works. Produced by Matt Holzman.